#include<stdio.h>

int mul(int m)
{
	if (m == 0 || m == 1)
		return 1;
	else
		return m * mul(m-1);
}

int main2()
{
	int m;
	printf("Please insert a number:\n");
	scanf("%d", &m);
	printf("%d de jie cheng shi: %d\n", m, mul(m));
	return 0;
}